Current Status and Future

Chapter 41 Current Status and Future



A Current Status and Future of Flexor Tendon Surgery


Peter C. Amadio, md



Current Status of Flexor Tendon Surgery


Tendon surgery has certainly advanced over the past century. Our repairs are stronger and more reproducible; most surgeons who deal with these injuries have had some sort of training in the management of tendon injuries, and within the past 60 years hand surgery has developed as a specialty, while within the past 30 years hand therapy has joined it as a recognized field of specialization. There are hand surgeons in nearly every country on the planet; in the larger and more developed countries, there are literally thousands of trained hand surgeons and therapists.


One might think that, with all this progress, tendon injuries would be a solved problem. But, despite our best efforts, this is not the case. The average result after surgery restores perhaps 80% of normal finger motion when both tendons are cut in zone 2, and that assumes a sharp laceration and a cooperative patient. Ragged cuts, multiple injuries, and patients who are not able or willing to cooperate with an early mobilization rehabilitation program still frequently end up with adhesions, ruptures, infections, contractures, and other forms of unsatisfactory results.


Why is this? Primarily because while our understanding of tendon healing, biomechanics, and physiology has grown dramatically, our ability to improve upon Mother Nature remains where it was in Sterling Bunnell’s day—or, for that matter, Galen’s. We may sometimes be able to avoid slowing down the healing process, by better techniques, but we have not yet found a method to speed things up. And we must face reality—tendon injuries are most common in those who can least afford time away from work for rehabilitation and protection—mostly adolescents and young adults, mostly male, and mostly in occupations where heavy use of both hands is an expectation. And, while our patients are often satisfied with less than normal motion, for many of them, joint contractures and loss of motion are unsightly at best, and functionally awkward for many. In short, while the current state of tendon surgery is better than it has ever been, it is not nearly as good as those with injured tendons want it to be.



The Future of Flexor Tendon Surgery


What does the future hold for tendon surgery? A good place to start is current research. These focus on two general areas—accelerating the pace of tendon healing and reducing adhesion formation. Along the way, researchers in both areas must address a common pitfall—too much load, too soon, will result in tendon rupture, and a need for the patient to start all over again.


Speeding up tendon healing has already run down one blind alley: once a tendon is moving, there is no evidence that more load on a repair speeds healing or reduces adhesions—all it can do is break the repair. Thus, the only reason to create ever stronger repairs is to permit a bit more of a margin of safety for early mobilization, while at the same time not creating so much bulk as to impede healing or gliding. In my opinion, there is little more we can practically do in this regard—current repairs are “good enough.”


What is needed to shorten tendon healing time? Two things—cells, and matrix, and these are interrelated, because making matrix requires cells—specifically, fibroblasts initially, and then tenocytes. Tendons are not very cellular, and the cells that are there are often trapped in a dense collagen matrix. Adding cells from outside the tendon should help, and there are several studies now underway in animal models that should be translatable to humans soon, delivering differentiated cells or stem cells, either via a cell-seeded patch of some sort between the cut tendon ends, or by literally attaching the cells to the tendon suture. Add in the right mix of cytokines, or perhaps even platelet-rich plasma, and we should be able to develop a cocktail that can cut down total healing time, and even better, accelerate the early healing phase, so that repair strength grows faster in the first few weeks, when the repair is in greatest jeopardy.


Reducing adhesions has always been possible, but at a price—aggressive mobilization may result in tendon rupture, and adhesion barriers are usually also healing barriers. New research into more permeable barrier, and ones that biodegrade over the critical first week or two, when most adhesions begin to form, may do the trick.


Finally, what to do when no tendon is available, due to extensive injury, tumor resection, or some other cause? Here, tissue engineering may help. While building a tendon from scratch is daunting, it may be possible to manipulate allograft tissue, seeding it with host cells, and specialized surfaces in the middle for gliding, and at the ends for attachment to tendon, muscle, or bone. Such work is already proceeding.


In short, I think that the future for tendon surgery is bright. With a decade, or two at the most, we should have solved the remaining vexing problems of healing and function and have begun to apply those solutions clinically. The best is yet to come.



B Current Status and Future


Robert Savage, mb, frcs, frcs ed orth, ms


A reasonable starting point for considering the future for tendon surgery would be to consolidate what we know of best practice today, and to ensure that this knowledge is as widely known as possible. Other chapters in this book cover this in detail and as previously reported in surgical history practitioners will choose which bits of advice are most believable and applicable. There now appears to be very strong evidence that multistrand tendon repairs give a more reliable outcome to acute tendon division. Hopefully, the use of two-strand core sutures is diminishing for it appears important that at least a four-strand core suture should be used. This should be combined with, at least, a simple peripheral suture but a crossed or interlocked peripheral suture adds further strength and gap resistance. A six-strand core suture further improves repair strength, but it is debatable whether addition of a crossed or interlocked peripheral suture is beneficial. All these elements give a repair that is, in the main, sufficiently robust to withstand the controlled active motion program and to reduce the chance of rupture in the healing phase.

Related posts:

Gene Therapy for Tendon Healing Treatment of the Flexor Tendon Sheath and Pulleys Tendon Friction, Lubrication, and Biomechanics of Motion Staged Tendon Grafts and Soft Tissue Coverage Outcomes of Flexor Tendon Repairs and Methods of Evaluation Customizing Flexor Rehabilitation Based on Zone or Type of Injury

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Mar 5, 2016 | Posted by in Hand surgery | Comments Off on Current Status and Future

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